Single-stream reactor operation

The input to each SCWO reactor will be an aqueous solution containing agent and energetics hydrolysates. Mixing these streams provides a single feed stream for the SCWO step and simplifies the overall process. In the reaction zone at the upper end of the reactor, oper-... 

Remark 3 Batch and semibatch reactors can also be studied by considering their space equivalent PFRs. The space equivalent of a single batch reactor can be regarded as a PFR with no side streams. The optimal holding time for the batch operation can be determined by the optimal PFR length and the assumed linear velocity of the fluid in the PFR. 

If the feed-stream conditions and the initial state in the reactor are known, Eq. (4-12) can always be integrated, although numerical procedures may be required. An important case in which analytical integration is possible is when the feed and exit flow rates, feed composition, and density are all constant and the reaction is first order. Piret and Mason have analyzed single and cascades (reactors in series) of stirred-tank reactors operating under these restrictions. The results are a reasonable representation of the behavior for many systems under startup and shutdown periods. With constant density, the concentration accounts fully for changes kt. amount of reactant. Also, constant density along with constant flow rates means that the reactor volume V will remain constant. Under these restrictions Eq. (4-12) may be written... 

Consider the possibifity of carrying out this reaction in a single continuous flow stirred-tank reactor operating at 75°C with a feed concentration of the benzotriazole eqnal to 15.10 X 10 M and a catalyst loading of 2.5 g/L. If the volume of the reactor is 4 m, determine the (different) volumetric flow rates of the feed stream that maximize the effluent concentrations of species B and C. Of the species of interest in the reaction network, only species A is present in the feed stream. 

Consider the reaction system and production requirements discussed in Illustration 10.1. Consider the possibility of using one or more continuous flow stirred-tank reactors operating in series. If each CSTR is to operate at 163 C and if the feed stream is to consist of pure A entering at 20 C, determine the reactor volumes and heat transfer requirements for (1) a single CSTR and (2) three identical CSTRs in series. 

The purpose of these sections is to match the temperature and pressure desired on the inlet streams to the reactor section and to the separation section. If the reactor operates at high tenperature (a common occurrence because this increases reaction rate), the reactor feed preparation and separator feed preparation sections are often combined in a single process-process heat exchanger. Such heat integration can be built into the base-case flowsheet, but, if not, it should be caught during the heat-integration step of... 

Fresh methanol, Stream 1, is combined with recycled reactant. Stream 14, and vaporized prior to being sent to a fixed-bed reactor operating between 250°C and 370°C. The single-pass conversion of methanol in the reactor is 80%. The reactor effluent, Stream 7, is then cooled prior to being sent to the first of two... 

In modem, single stream ammonia plants there is little scope in the design to make significant changes to the operating conditions in any of the individual catalyst reactors. Operating conditions for the carbon monoxide conversion reaction are shown in Table 9.14. The only practical variable is operating temperature which can be slowly increased as catalyst loses activity. 

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

Wetox uses a single-reactor vessel that is baffled to simulate multiple stages. The design allows for higher destmction efficiency at lower power input and reduced temperature. Its commercial use has been limited to one faciHty in Canada for treatment of a complex industrial waste stream. Kenox Corp. (North York, Ontario, Canada) has developed a wet oxidation reactor design (28). The system operates at 4.1—4.7 MPa (600 to 680 psi) with air, using a static mixer to achieve good dispersion of Hquid and air bubbles. 

In two processes under development as of 1997, the sulfur dioxide stream reacts with reduciag gas over a proprietary catalyst to form elemental sulfur. Both processes have achieved a sulfur recovery of 96% ia a single reactor. Multiple reactor systems are expected to achieve 99+% recovery of the feed sulfur. The direct sulfur recovery process (DSRP), under development at Research Triangle Institute, operates at high temperature and pressure. A similar process being developed at Lawrence Berkeley Laboratory is expected to operate near atmospheric pressure. 

Based on these results, the optimal single interception for the problem is to use activated Carbon adsorption to separate CE fhim the gaseous stream leaving the reactor (t> = 1) and reduce its composition to y " = 4.55 ppmw CE (which corresponds to removing 4.57 x 10 kg CE/s from v = 1). The optimal solution has a minimum operating cost of approximately 576,250/yr. Several important observations can be drawn from the list of generated solutions ... 

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